US5291326A - Optical signal transmission system, particularly optical cable television system, with monitoring and service-channel facilities - Google Patents

Optical signal transmission system, particularly optical cable television system, with monitoring and service-channel facilities Download PDF

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Publication number
US5291326A
US5291326A US07/855,615 US85561592A US5291326A US 5291326 A US5291326 A US 5291326A US 85561592 A US85561592 A US 85561592A US 5291326 A US5291326 A US 5291326A
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United States
Prior art keywords
signal
transmitter
auxiliary
auxiliary signal
laser
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Expired - Lifetime
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US07/855,615
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English (en)
Inventor
Rolf Heidemann
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Alcatel Lucent NV
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Alcatel NV
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/07—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems
    • H04B10/075—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal
    • H04B10/077—Arrangements for monitoring or testing transmission systems; Arrangements for fault measurement of transmission systems using an in-service signal using a supervisory or additional signal
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2210/00—Indexing scheme relating to optical transmission systems
    • H04B2210/07—Monitoring an optical transmission system using a supervisory signal
    • H04B2210/078—Monitoring an optical transmission system using a supervisory signal using a separate wavelength

Definitions

  • a system for optically transmitting a useful signal from a transmitter over an optical waveguide (3) or a fiber-optic network to a receiver characterized in that in addition to the useful signal (S 1 ), the transmitter (1) transmits an auxiliary signal (S 2 ), that the useful signal and the auxiliary signal are transmitted over the same optical waveguide (3) or the same fiber-optic network toward the receiver (2) at different wavelengths, that at a desired point in the transmission link, means (4a, 4b, 5, 6, 7) are provided for extracting and analyzing the auxiliary signal (S 2 ) and for transmitting the results of the analysis, if necessary together with other information, as a response signal (S 3 ) over the same optical waveguide (3) or the same fiber-optic network to the transmitter (1), and that the transmitter includes means for controlling the further transmission of the useful signal and the auxiliary signal in accordance with the response signal.
  • auxiliary signal (S 2 ) is transmitted and the laser of the pump source (7) are so chosen that the auxiliary signal can be passed through the laser without being changed and without interfering with the operation of the laser.
  • the principle consists in the fact that the transmitter, besides transmitting the useful signal, sends out an auxiliary signal at another wavelength. Because of the different wavelengths, the auxiliary signal can be extracted from the optical waveguide at the monitoring point and then be used to indirectly monitor the quality of the useful signal.
  • the auxiliary signal After being separated from the useful signal, the auxiliary signal is converted to an electric signal and analyzed. The results of the analysis are sent in the form of a response signal to the transmitter. The latter controls the further transmission of the useful and auxiliary signals in accordance with the information contained in the response signal.
  • the auxiliary signal need not be transmitted continuously but may also be sent from time to time. It may be an analog or digital signal, a test signal with variable or invariable message content, a voice signal from the operators, and the like. The same applies to the response signal.
  • system according to the invention can also be used for interactive communication between units or persons at the monitoring point and units or persons at the transmitter. This use corresponds to that of a service channel.
  • FIG. 1 is a block diagram of the system for transmitting a useful signal and an auxiliary signal and for monitoring the auxiliary signal at a desired point so as to generate a response signal that is sent back to the transmitter.
  • FIG. 2 is a block diagram of the system showing a fiber-optic amplifier.
  • FIG. 3 shows an alternative version of the system of FIG. 2.
  • FIG. 1 shows a transmitter 1, a receiver 2, an optical waveguide 3 interconnecting the transmitter and receiver, a monitoring point with a first coupler 4a and a second coupler 4b, a photodiode 5, a monitoring device 6, a light source 7, a useful signal S 1 , an auxiliary signal S 2 , and a response signal S 3 .
  • the first coupler 4a extracts the auxiliary signal S 2 from the optical waveguide 3, so that it can be passed to the photodiode 5.
  • the latter converts the optical auxiliary signal S 2 to an electric signal.
  • the monitoring device 6 analyzes the electric signal and, together with the light source 7, generates the optical response signal S 3 .
  • This response signal is coupled by the coupler 4b into the optical waveguide 3 in a direction opposite to that of the useful signal, thus conveying to the transmitter 1 information that can be used for the further transmission of the useful signal S 1 and the auxiliary signal S 2 .
  • the transmitter may, for example, be part of the center ("head end") of an optical cable-television network, the receiver a TV set, and the monitoring point a subscriber entrance unit or a so-called network termination point.
  • the invention can be used in connection with any application where a transmitter is connected via an optical waveguide to a receiver or via a fiber-optic network to many receivers and where signal monitoring is to take place somewhere between the transmitter and the receiver(s).
  • the signal monitoring is combinbed with signal amplification.
  • the pump source of this amplifier can also be used to generate the response signal.
  • the pump light is coupled into the light-amplifying length of fiber in a direction opposite to that of the useful signal.
  • the monitoring device produces art electric response signal and modulates the pump source therewith. The pump light thus conveys a message from the monitoring point to the transmitter.
  • the modulation of the pump light is an intensity modulation.
  • the modulation frequency must be high enough to ensure that the gain of the light-amplifying length of fiber is not modulated.
  • the bandwidth of the response signal must be so small that the signal can still be interpreted after travelling the path to the transmitter, i.e., despite the attenuation introduced on this path. However, this does not impose any limit that could invalidate the principle.
  • FIG. 2 An embodiment of a system combining signal monitoring and signal amplification in accordance with the invention is shown in FIG. 2. There, all elements correspond to those of FIG. 1 except that a light-amplifying length of fiber 8 has been added, that the wavelength of the signal S 3 is the pump wavelength, and that the internal construction of the monitoring device 6 is different if necessary.
  • the light source will be transparent to the auxiliary signal.
  • the auxiliary signal can be passed through the light source without interfering with and being altered by the latter.
  • FIG. 3 The simplified version of the system of FIG. 2 is shown in FIG. 3.
  • the light source 7 of FIG. 3 includes a photodiode 11 as is commonly used to monitor the laser.
  • this photodiode 11 receives not only the backface emission of the laser as usual, but also the auxiliary signal. Since the backface emission of the laser contains mainly low-frequency components white the auxiliary signal contains mainly high-frequency components, the two signals can be readily separated in the monitoring device and processed separately.
  • the analysis of the backface emission gives information on the condition of the laser.
  • the backface emission can also be used as usual to regulate the average pump power of the laser.
  • the light source 7, namely its photodiode 11, is connected to the monitoring device 6 by a line over which the received auxiliary signal and the electric signal formed from the backface emission of the laser are transferred to the monitoring device 6.
  • a second line between the monitoring device 6 and the light source 7, namely the laser 10 of the source, serves to supply an electric response signal to the laser, which converts this signal to an optical response signal.
  • the transmission quality of the useful signal can be inferred from the transmission quality of the auxiliary signal.
  • the ratio of the attenuation of two signals of different wavelength on a link of a given length is known, so that the attenuation of the useful signal can be inferred from the attenuation of the auxiliary signal.
  • a failure of the auxiliary signal to appear indicates a break in the fiber-optic link.
  • S 2 and S 3 can also be used to set up a so-called service channel.
  • the useful signal and the auxiliary signal may, of course, be composed of two or more signals, and that it is also within the scope of the invention to use two or more auxiliary signals on two or more wavelengths for the purpose of monitoring the useful signal(s) at different points of the transmission link or for service-channel purposes.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)
  • Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)
  • Monitoring And Testing Of Transmission In General (AREA)
  • Small-Scale Networks (AREA)
  • Selective Calling Equipment (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
US07/855,615 1991-03-23 1992-03-20 Optical signal transmission system, particularly optical cable television system, with monitoring and service-channel facilities Expired - Lifetime US5291326A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4109683A DE4109683A1 (de) 1991-03-23 1991-03-23 System fuer optische signaluebertragung, insbesondere optisches kabelfernsehsystem, mit ueberwachungs- und dienstkanaleinrichtung
DE4109683 1991-03-23

Publications (1)

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US5291326A true US5291326A (en) 1994-03-01

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US (1) US5291326A (de)
EP (1) EP0505829B1 (de)
JP (1) JPH05122706A (de)
AT (1) ATE147212T1 (de)
AU (1) AU643370B2 (de)
CA (1) CA2063666C (de)
DE (2) DE4109683A1 (de)
DK (1) DK0505829T3 (de)
ES (1) ES2098384T3 (de)
NZ (1) NZ241946A (de)

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5355248A (en) * 1992-10-30 1994-10-11 Northern Telecom Limited Optical amplifier
US5453872A (en) * 1993-07-26 1995-09-26 Alcatel N.V. Fiber-optic amplifier as wavelength converter
US5491572A (en) * 1993-09-16 1996-02-13 Fujitsu Limited Method and system for detecting trouble in two-way single-fiber optical transmission
US5495362A (en) * 1994-04-13 1996-02-27 Ando Electric Co., Ltd. Photoperiodic circuit amplification control apparatus
US5532865A (en) * 1992-10-09 1996-07-02 Matsushita Electric Industrial Co., Ltd. Fiber optic communication terminal, fiber optic communication system, and its wavelength setting method
US5532864A (en) * 1995-06-01 1996-07-02 Ciena Corporation Optical monitoring channel for wavelength division multiplexed optical communication system
US5539570A (en) * 1995-03-21 1996-07-23 Nec Corporation Monitoring state of optical elements in an optical amplifier
GB2314224A (en) * 1996-06-11 1997-12-17 Stc Submarine Systems Ltd Fibre optic transmission
US5706112A (en) * 1995-10-23 1998-01-06 Fujitsu Limited Light signal remote control apparatus and light signal level controlling method
US5729373A (en) * 1994-11-16 1998-03-17 Nec Corporation Reproducing circuit of monitor signal
US5751458A (en) * 1995-03-15 1998-05-12 Nec Corporation Optical double transmission system
US5798853A (en) * 1992-10-16 1998-08-25 Fujitsu, Limited Optical communication system compensating for chromatic dispersion and phase conjugate light generator for use therewith
US5923463A (en) * 1996-10-02 1999-07-13 Nec Corporation Optical amplifier and method for controlling the same
EP0935355A3 (de) * 1998-02-05 1999-12-22 Lucent Technologies Inc. System und Vorrichtung zur Überwachung und Kennzeichnung von optischen Verbindungen
US6233076B1 (en) * 1996-09-17 2001-05-15 Fujitsu Limited Optical communications system
US6266169B1 (en) * 1992-04-08 2001-07-24 Hitachi, Ltd. Optical transmission equipment which transmits an amplified optical data signal and an optical surveillance signal
GB2378832A (en) * 2001-08-14 2003-02-19 Fujitsu Ltd Remote optical repeater monitoring
US20030103536A1 (en) * 2000-01-13 2003-06-05 Leggett Derek Nigel Optical supply arrangement
US6748342B1 (en) 1999-04-20 2004-06-08 Nokia Corporation Method and monitoring device for monitoring the quality of data transmission over analog lines
US20040175171A1 (en) * 2003-03-07 2004-09-09 Verizon Services, Corp. Testing a fiber link in a communication system without interrupting service
US6819830B2 (en) * 2002-03-12 2004-11-16 Ciena Corporation System and method for communicating data in a network using backchannel signaling
EP1033833A3 (de) * 1999-03-04 2004-12-29 Siemens Aktiengesellschaft Verfahren zur Überwachung des Betriebes von optischen Fasern
EP1215836A3 (de) * 2000-12-14 2005-08-31 Alcatel USA Sourcing, L.P. Wellenlängenagiler optischer Transponder zur Prüfung von bidirektionalen einzigen-Lichtleitfaser WDM System
US20110261440A1 (en) * 2008-11-02 2011-10-27 Elbit Systems Electro-Optics Elop Ltd. Modulation of fiber laser pumped difference frequency generator

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2285192A (en) * 1993-12-07 1995-06-28 Northern Telecom Ltd Network surveillance
DE4342792A1 (de) * 1993-12-15 1995-06-22 Siemens Ag Überwachung optischer Breitband-Anschlußleitungen bis zu einer passiven Schnittstelle
DE19538755A1 (de) * 1995-10-18 1997-04-24 Bosch Gmbh Robert Überwachungs- und/oder Steuereinrichtung und -Verfahren
DE19963803A1 (de) * 1999-12-30 2001-07-26 Siemens Ag Verfahren und Anordnung zur Einstellung der Frequenz eines Sendelasers

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6399633A (ja) * 1986-10-15 1988-04-30 Nec Corp 光フアイバ通信回線の常時障害監視システム
US4994675A (en) * 1989-04-28 1991-02-19 Rebo Research, Inc. Method and apparatus for checking continuity of optic transmission
EP0415438A2 (de) * 1989-08-31 1991-03-06 Fujitsu Limited Optischer Verstärker und optisches Übertragungssystem mit dem optischen Verstärker
EP0449475A2 (de) * 1990-03-26 1991-10-02 AT&T Corp. Telemetrie für optischen Faserzwischenverstärker
US5058103A (en) * 1988-11-08 1991-10-15 Fujitsu Limited Bidirectional optical transmission system having a light-interruption detecting function
US5162936A (en) * 1990-03-01 1992-11-10 Kokusai Denshin Denwa Company, Ltd. Apparatus for monitoring the operation of an optical repeater

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61232734A (ja) * 1985-04-08 1986-10-17 Mitsubishi Electric Corp 光伝送回路
JPS6276331A (ja) * 1985-09-27 1987-04-08 Nec Corp 双方向光フアイバ通信方式
GB8709900D0 (en) * 1987-04-27 1987-08-05 British Telecomm Surveillance system
GB8906937D0 (en) * 1989-03-28 1989-05-10 Plessey Telecomm Testing optical fibre links
CA2068926C (en) * 1991-09-03 1997-08-26 Cleo D. Anderson Optical line monitor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6399633A (ja) * 1986-10-15 1988-04-30 Nec Corp 光フアイバ通信回線の常時障害監視システム
US5058103A (en) * 1988-11-08 1991-10-15 Fujitsu Limited Bidirectional optical transmission system having a light-interruption detecting function
US4994675A (en) * 1989-04-28 1991-02-19 Rebo Research, Inc. Method and apparatus for checking continuity of optic transmission
EP0415438A2 (de) * 1989-08-31 1991-03-06 Fujitsu Limited Optischer Verstärker und optisches Übertragungssystem mit dem optischen Verstärker
US5162936A (en) * 1990-03-01 1992-11-10 Kokusai Denshin Denwa Company, Ltd. Apparatus for monitoring the operation of an optical repeater
EP0449475A2 (de) * 1990-03-26 1991-10-02 AT&T Corp. Telemetrie für optischen Faserzwischenverstärker

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
"B-ISDN", G. H. Doman, Journal of Lightwave Technology, vol. 6 No. 11, Nov. 1988, pp. 1720-1727.
B ISDN , G. H. Doman, Journal of Lightwave Technology , vol. 6 No. 11, Nov. 1988, pp. 1720 1727. *
Patent Abstract of Japan, vol. 12, No. 337 (E 657) 1988 & JP A 63 099 633 (NEC) *Zusammenfassung*. *
Patent Abstract of Japan, vol. 12, No. 337 (E-657) 1988 & JP-A-63 099 633 (NEC) *Zusammenfassung*.
Patent Abstracts of Japan vol. 13, No. 280 (E 779( 1989 J JP A 10 65 938 (Nippon) *Zusammenfassung*. *
Patent Abstracts of Japan vol. 13, No. 280 (E-779( 1989 J JP-A-10 65 938 (Nippon) *Zusammenfassung*.

Cited By (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6266169B1 (en) * 1992-04-08 2001-07-24 Hitachi, Ltd. Optical transmission equipment which transmits an amplified optical data signal and an optical surveillance signal
US20040161189A1 (en) * 1992-04-08 2004-08-19 Hitachi, Ltd. Optical transmission system constructing method and system
US7167652B2 (en) 1992-04-08 2007-01-23 Hitachi, Ltd Optical transmission system constructing method and system
US6728489B2 (en) 1992-04-08 2004-04-27 Hitachi, Ltd. Optical transmission system constructing method and system
US7292785B2 (en) 1992-04-08 2007-11-06 Hitachi, Ltd. Optical transmission system constructing method and system
US20070053687A1 (en) * 1992-04-08 2007-03-08 Keiji Tomooka Optical transmission system constructing method and system
US5532865A (en) * 1992-10-09 1996-07-02 Matsushita Electric Industrial Co., Ltd. Fiber optic communication terminal, fiber optic communication system, and its wavelength setting method
US5798853A (en) * 1992-10-16 1998-08-25 Fujitsu, Limited Optical communication system compensating for chromatic dispersion and phase conjugate light generator for use therewith
US5355248A (en) * 1992-10-30 1994-10-11 Northern Telecom Limited Optical amplifier
US5453872A (en) * 1993-07-26 1995-09-26 Alcatel N.V. Fiber-optic amplifier as wavelength converter
US5491572A (en) * 1993-09-16 1996-02-13 Fujitsu Limited Method and system for detecting trouble in two-way single-fiber optical transmission
US5495362A (en) * 1994-04-13 1996-02-27 Ando Electric Co., Ltd. Photoperiodic circuit amplification control apparatus
US5729373A (en) * 1994-11-16 1998-03-17 Nec Corporation Reproducing circuit of monitor signal
US5751458A (en) * 1995-03-15 1998-05-12 Nec Corporation Optical double transmission system
US5539570A (en) * 1995-03-21 1996-07-23 Nec Corporation Monitoring state of optical elements in an optical amplifier
US5798855A (en) * 1995-06-01 1998-08-25 Ciena Corporation Optical monitoring channel for wavelength division multiplexed optical communication system
US5532864A (en) * 1995-06-01 1996-07-02 Ciena Corporation Optical monitoring channel for wavelength division multiplexed optical communication system
US5706112A (en) * 1995-10-23 1998-01-06 Fujitsu Limited Light signal remote control apparatus and light signal level controlling method
GB2314224A (en) * 1996-06-11 1997-12-17 Stc Submarine Systems Ltd Fibre optic transmission
US6233076B1 (en) * 1996-09-17 2001-05-15 Fujitsu Limited Optical communications system
US6414770B2 (en) * 1996-09-17 2002-07-02 Fujitsu Limited Optical communications system
US6721507B2 (en) 1996-09-17 2004-04-13 Fujitsu Limited Optical communications system
US5923463A (en) * 1996-10-02 1999-07-13 Nec Corporation Optical amplifier and method for controlling the same
EP0935355A3 (de) * 1998-02-05 1999-12-22 Lucent Technologies Inc. System und Vorrichtung zur Überwachung und Kennzeichnung von optischen Verbindungen
EP1033833A3 (de) * 1999-03-04 2004-12-29 Siemens Aktiengesellschaft Verfahren zur Überwachung des Betriebes von optischen Fasern
US6748342B1 (en) 1999-04-20 2004-06-08 Nokia Corporation Method and monitoring device for monitoring the quality of data transmission over analog lines
US7787504B2 (en) * 2000-01-13 2010-08-31 Schlumberger Technology Corporation Optical supply arrangement
US20030103536A1 (en) * 2000-01-13 2003-06-05 Leggett Derek Nigel Optical supply arrangement
EP1215836A3 (de) * 2000-12-14 2005-08-31 Alcatel USA Sourcing, L.P. Wellenlängenagiler optischer Transponder zur Prüfung von bidirektionalen einzigen-Lichtleitfaser WDM System
US6980745B2 (en) 2001-08-14 2005-12-27 Fujitsu Limited Optical transmission system
GB2378832A (en) * 2001-08-14 2003-02-19 Fujitsu Ltd Remote optical repeater monitoring
GB2378832B (en) * 2001-08-14 2004-12-15 Fujitsu Ltd Optical transmission system
US6819830B2 (en) * 2002-03-12 2004-11-16 Ciena Corporation System and method for communicating data in a network using backchannel signaling
US20040175171A1 (en) * 2003-03-07 2004-09-09 Verizon Services, Corp. Testing a fiber link in a communication system without interrupting service
US7561798B2 (en) * 2003-03-07 2009-07-14 Verizon Services Corp. Testing a fiber link in a communication system without interrupting service
US20090257747A1 (en) * 2003-03-07 2009-10-15 Kokkinos Dimitrios S Testing a fiber link in a communication system without interrupting service
US20110261440A1 (en) * 2008-11-02 2011-10-27 Elbit Systems Electro-Optics Elop Ltd. Modulation of fiber laser pumped difference frequency generator
US9130351B2 (en) * 2008-11-02 2015-09-08 Elbit Systems Electro-Optics Elop Ltd. Modulation of fiber laser pumped difference frequency generator

Also Published As

Publication number Publication date
DE59207791D1 (de) 1997-02-13
DK0505829T3 (da) 1997-06-23
EP0505829A2 (de) 1992-09-30
NZ241946A (en) 1994-07-26
JPH05122706A (ja) 1993-05-18
CA2063666A1 (en) 1992-09-24
CA2063666C (en) 1998-04-14
EP0505829B1 (de) 1997-01-02
ATE147212T1 (de) 1997-01-15
DE4109683A1 (de) 1992-09-24
EP0505829A3 (en) 1993-03-03
ES2098384T3 (es) 1997-05-01
AU643370B2 (en) 1993-11-11
AU1216092A (en) 1992-09-24

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